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            <h2 class="title"><a id="Cursors"></a>Chapter 9. Using Cursors</h2>
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          <b>Table of Contents</b>
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        <dl>
          <dt>
            <span class="sect1">
              <a href="Cursors.html#openCursor">Opening and Closing Cursors</a>
            </span>
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          <dt>
            <span class="sect1">
              <a href="Positioning.html">Getting Records Using the Cursor</a>
            </span>
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          <dd>
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              <dt>
                <span class="sect2">
                  <a href="Positioning.html#cursorsearch">Searching for Records</a>
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              <dt>
                <span class="sect2">
                  <a href="Positioning.html#getdups">Working with Duplicate Records</a>
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          </dd>
          <dt>
            <span class="sect1">
              <a href="PutEntryWCursor.html">Putting Records Using Cursors</a>
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          <dt>
            <span class="sect1">
              <a href="DeleteEntryWCursor.html">Deleting Records Using Cursors</a>
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          <dt>
            <span class="sect1">
              <a href="ReplacingEntryWCursor.html">Replacing Records Using Cursors</a>
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            <span class="sect1">
              <a href="cursorJavaUsage.html">Cursor Example</a>
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      <p>
	Cursors provide a mechanism by which you can iterate over the records in a
	database. Using cursors, you can get, put, and delete database records.  If
	a database allows duplicate records, then cursors are 
    
    

    <span>the easiest way that you can access anything
    other than the first record for a given key.</span>
  </p>
      <p>
	This chapter introduces cursors. It explains how to open and close them, how
	to use them to modify databases, and how to use them with duplicate records.
  </p>
      <div class="sect1" lang="en" xml:lang="en">
        <div class="titlepage">
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            <div>
              <h2 class="title" style="clear: both"><a id="openCursor"></a>Opening and Closing Cursors</h2>
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        <p>
		To use a cursor, you must open it using the <code class="methodname">Database.openCursor()</code> 
		method. When you open a
		cursor, you can optionally pass it a <code class="classname">CursorConfig</code> 
		object to set cursor properties. 
        
        <span>
                The cursor properties that you can set allows you to
                control the isolation level that the cursor will obey. See
                the
                <em class="citetitle">Berkeley DB Getting Started with Transaction Processing</em> guide for more
                information.
        </span>
	</p>
        <p>For example:</p>
        <a id="java_cursor1"></a>
        <pre class="programlisting">package db.GettingStarted;
    
import com.sleepycat.db.Cursor;
import com.sleepycat.db.Database;
import com.sleepycat.db.DatabaseException;

import java.io.FileNotFoundException;

...
Database myDatabase = null;
Cursor myCursor = null;

try {
    myDatabase = new Database("myDB", null, null);

    myCursor = myDatabase.openCursor(null, null);
} catch (FileNotFoundException fnfe) {
    // Exception handling goes here ...
} catch (DatabaseException dbe) {
    // Exception handling goes here ...
}</pre>
        <p>
        To close the cursor, call the <code class="methodname">Cursor.close()</code>
        method. Note that if you close a database that has cursors open in it,
        then it will throw an exception and close any open cursors for you. 
        For best results, close your cursors from within a 
        <code class="literal">finally</code> block. However, it is recommended that you always close all cursor handles immediately after their use to ensure concurrency and to release resources such as page locks. 
        
    </p>
        <a id="java_cursor2"></a>
        <pre class="programlisting">package db.GettingStarted;
    
import com.sleepycat.db.Cursor;
import com.sleepycat.db.Database;

...
try {
    ...
} catch ... {
} finally {
    try {
        if (myCursor != null) {
            myCursor.close();
        }

        if (myDatabase != null) {
            myDatabase.close();
        }
    } catch(DatabaseException dbe) {
        System.err.println("Error in close: " + dbe.toString());
    }
} </pre>
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